Ammunition belt feed system for automatic firearms



March 3, 1959 R. s. ROBINSON 2,875,671

AMMUNITION BELT FEED SYSTEM FOR AUTOMATIC FIREARMS Filed Aug. 6, 1955 4'Sheets-Sheet 1 INVENTOR ATTORNEYS March 3; 1959 R. s. ROBINSON 2,875,671

AMMUNITION BELT FEED SYSTEM FOR AUTOMATIC FIREARMS Filed Aug. 6, 1953 4 Sheets-Sheet 2 I n 1 G4 7 I B 65 7*? 9, ,5. 5U x x I ATTQRNEYJ K INVENTOR 7 March 3, 1959 R. s. ROBINSON 2,875,671

' AMMUNITION BELT FEED SYSTEM FOR AUTOMATIC FIREARMS Filed Aug. 6, 1953 4 Sheets-Sheet 3 INVENTOR W1 BY 6 ATTORNEYS March 3, 1959 R. s. ROBINSON 2,875,671

AMMUNITION BELT FEED SYSTEM FOR AUTOMATIC FIREARMS Filed Aug. 6, 1953 4 Sheets-Sheet 4 ATTORNEYS 'belt and inserted into the chamber.

,and effect the feed of the belt.

States Patent 16 chim c1. 89-33) This invention relates to automatic firearms, andpertains more particularly to the feed mechanism for-feeding the. ammunition to anautomatic firearm which employs a belt by which the ammunition is carriedto the firearm to be loaded into the chamber for firing- The majority of feeding mechanisms in general use for belt-fed automatic firearms are so constructed as to perform round-by-round feed of the ammunition belt during either the forward or rearward movement of the reciprocable part of the mechanism, whether this part be the barrel extension, the breech bolt, or other recoiling member such as a gas-operated piston. belt is held substantially at rest during the other part of the movement so that the cartridge which has been centered or. moved .to apoint. in the verticaliplane ofthe chamber can be extracted from or, rammed out of the Such a feed system results, of course, in an intermittent feedof the belt as the latter is moved a full cartridge pitch duringone half stroke of each operating cycle. The term, cartridge pitch is used to refer to thedistance between the centers of two adjacent cartridges in the belt.

achieved either during one movement or during both forward and rearward movement of the recoiling member, in preferably is effected partly during one of these moveanents and partly during the other. This is accomplished by use ofa longitudinally sliding cam plate which is fixed during normal operation of the firearm to the recoiling member. This cam plate is provided withone or more cam grooves in each of'which is located a follower, which follower is carried by a transverse sliding :member or members, each of which carries a belt-feed pawl to engage a part of the belt or the cartridges therein In such systems the in constructions according to the invention, where feed fis performed during-both rearward and. forward movement ofthe recoiling member, the heavily accfilerated, Ireciprocating motion of the recoiling member may be made to perform a unidirectional, substantially constant speed and uninterrupted feed of the ammunition belt by firstly contouring each cam groove so as to resemble "closely the velocity-time diagram of the forward or rearward movement of the recoiling member during which the feed .pawl operating from that cam groove is active,

thereby achieving a substantially constant lateral velocity in each feed pawl during its active or feeding stroke, and

.;secondly, by constructing the lateral stroke of each cam ,groove ,to be proportional to the time occupied bythe rearward or forward movement of the member :during which the feed pawl operatingfrom that cam groove is ,active, thereby achieving. asubstantially equal velocity for both feed pawls during theirrespective active strokes.

3i In knownbelt feed systems which are applied to' the type ofbelt from which the cartridges are rammed forwardly' out of the belt,"the' centrally fed cartridge" usually :2 a has to be thrust downwardly immediately before ramming to place it in the correct level and attitude for ramming, and in some cases itis partially or fully'removed from the belt before ramming. In some instances this function is performedby a spring action and in other cases by the positive action of a member operated through the movement of the pawl carrier. jAccording to-the presentinvention this function is performed by the action of oneor more transversely pivoted members which are actuated by lugs or cam faces constructed upon the longitudinally sliding cam plate. I

Also the belt feed system of known automatic firearms is usually constructed either wholly or partly into the hinged or removable cover of the firearm, and the opening or removing of this cover is usually necessary and desirable in connection with introducing theloaded belt into the gunJQAsthe belt feed system-is actuated by a recoiling member housed within the receiver or breech casing,,wh ich must register with some part of the belt feed system when the firearm is ready for action in order tosecuregcorrect operation 'of the feedsystem, it is very often necessary in present constructions forthe movement of one of the parts to be efiected or maintained manually during the process ofclosing or replacing the cover in order to secure the correct registration of mating members which connect the recoilingmember to a part of the feed system carried-by the cover In accordance with the present invention, :the connection of the feed system to the recoiling member by which it is operated isachieved by means of a vertical plunger carried bythe recoiling member andengag'ing slides forward under the cam plate, at which time it'may rise and engage the point where the recess occurs in the cam plate, and the bevel lug or lugs simultaneously rising into non-engagingvoids or oversize holes in the cam plate. 'Q'YQ One object of the invention is to provide a new and improved feed system for automatic firearms.

A still further object of the invention is to proy'ide a new and improved feed systemvfor automatic firearms whereinia longitudinally "slidable cam plate actuatedfby [a recoiling member isadapted to, effect actuation 'of transversely slidable members, the-latter members carrying pawl fingers to efiect the feeding of the belt.

A still further object of the invention is to provide a belt-feed mechanism of the character described wherein proved means o'fcbnhctidiibetween the recoiling Inember and the cam-plate actuator for the feed mechanism whereby these two elements -will be automatically-coin:

nected upon'opening and closing of the cover-of the firearm without the necessity of any manual etfortf-tp efiect such I. .QQ... 1;; 1:

inga furthermodified form of my' in'ventiony of Figylly" I in another position; I I

Fig. 14 is a view similar to Figs 12 showing the parts carried by the recoiling member. 1 i

. To illustrate 'oue embodimentof "my invention I have shown in Figs. 1 to of the drawings a firearm compris- I ing a receive 10, a band 11 fixed thereto, the barrel. being' provided at its breech end with the usual charm ber 12. A cover or feed housing 13 may be hinged to having one' form of my invention. applied thereto, 5

Fig.2 is a horizontal sectionalview on line 2--'2ot Fi'gl3 is a view in another position; i

Fig. 4 is a sectional viewon'line' 4-4 of Fig. 2;

- Fig. 5 is a detail perspective view'ofthe'plunger and rear portion of the cam plate by'which these parts are connected;

Fig. 6 is a vertical sectional-view through a firearm showing a modified form ormy invention;

Fig. 7 is a view similar to Fig. 6 showing the parts in another position; i 1

Fig. la is a horizontal seasonal new line; s -s of siinilar to Fig. 2 but showing the parts $4-norma11yrests against the shoulder 35 oaths member 13, thisplunger 32 acting as a resilient stop for the;

cam plate 30.

Thiscarn plate is; providedadjacent its rear endwith 1 an opening 36 of relatively small diameterand an open-- ing 37 of greater width than the opening 36. Mounted ,in a socket in therecoiling member (which in this inisa: beveled lug.44 oficonsiderably; greater width than the boss 45; which lug is adapted 03136. received in the opening 37 of the cam plate. The opening 37 provides Fig. 9 is a view' similar'to '8 showing the parts" in,

another position;

Fig. 10 is a sectional view on line" Iii-+10 of Fig. 9;

Fig. 11 isavertical sectional viewiof a firearm" showr a 'Fig. '12is a "ho "zontal sectional iew on 1i Fig. 13 is'a view similar to in position'of FigQlS;

Fig. l6fis a detail perspective view of the plunger the receiver at Hand latchedinplace by anyusual means, notshown. v p

A feed chute 15 is mounted infixed position within the receiver, this feed chute beingof proper cross sectional shapeto receiveand guide therethrough the cartridges in an ammunition belt 16, the cartridges being shownin dotted lines at 17, 18 and 19. This feed chute'is provided with a slotzn in ,its rear .face to permit rearward eiitra'c'tion therefrom of the cartridges when the latter have been fed into a central position with respect to "the chamber.

The cartridges may be extracted from the belt by the reciprocatiiigbolt 21, which for this purpose is provided with resilient extractor members 22 which may engage theses: ofa cartridge in the ammunition belt whenthe cartridge is at'it's central position. Pivoted to the bolt 21 is a lever 23 having a guide lug 24 adjacent itsforwaild end which rides in a cam groove 25 ,in the housing wa laterally or transversely and is adapted to engage the cartridge as it is moved rearwardly from the ammunition )belt by the:bolt and force it downwardly in line with the chamber 12, as shown, for example, at 27 in Fig. 1. In this position the cartridge is held the extractor members 28 which are also secured to the ,bolt, and it will be understood that in its'movement downwardly from its level in the ammunition belt. to the level of the chamber, it slides downwardly from -the .e ttractors 22 to; the extractors 2 8.

left, as shown in Fig. l, by a springH SS so thatits head Fig. 11 showing the parts t Fi is a horizontal "sectional view on, lin'e-15--;t5 0Fig.?1 2;and H ment, of Ythebolt without any attention on the part of The forward IldIZG Of the lever '23 is turned stance is illustrated as thebolt. 21) is a plunger 38 spring pressed upwardly by the spring 39, the movement of the plunger being limited by. a pin 40 secured to the bolt 1 t and disposed within a slot 41 in the plunger 38. 7

i The plunger 38 carries. at its upper end .a plate 42 which. supports a stud or .boss 43 adapted to fit fairly,

. snugly in the opening36of the cam plate 30 80, as to provide anoperating connection between these parts and member or bolt21. Mounted forwardly of the boss'43 ample.clearance :forthelug 44 so that the latter is ,in- I operative during the firing of the gun. It will beapparent, i I I however, that the boss 48 cannot enter the opening 36 until thelug: 44 registers with the opening 37. and that,

as the beveled surface of the member 44 faces'forwardly, the bolt or recoiling member may move forwardly I I withtrespec't' to thel cam plate when the members are, not

engaged, and 'upon such relative movement the plunger 38 will. be cammed downwardly in the socket. of the bolt 7 by the beveledlugid l. However, when the member 44 registers with the. opening 37, the plunger will spring upwardly and engagethebossAB in the opening ,36.

will register and become engaged upon forward move:

the operator. 7 v p Slidably mounted uponthe under-surface of the housing member 13and belowthe cam plate 30 are slide mem 'bers 45, 46 and 47, the latter being intermediate thev members 45 and 46. These members may be held in place by a guide or guides 48 so that they have freeslidingmovement transversely of the axis of the firearm. Each of thesemembers carryspring-pressed pawl members, those connected with the slides 45 and 46 being designated by the numeral 49, while the pawl member 50 is connected 'to the slide 47. i The connection between these ,pawls and their slide members is a pivotalonc, and the pawls are urged outwardly from the slides or downwardly, as shown in Fig. 4, by springs SI and 52- so that the pawls will i be urged into engagement with the cartridges in the belt 16: i i l The cam' plate 30is provided with a cam groove 55 within whichridesa .cam follower 56 secured to the intermediate pawl slide 47. FromlFigs. 2 audit it will be apparcntthanas the cam slide is reciprocated longitudinally by'the recoiling menibenthe cam slot 55 will, by reason of the engagement of the :cam follower 56-therein, effect transverse reciprocation of the slide47. At its rear end the cam slot 55 is provided with a portionSS which is substantially in line with the axis ofthe gun butthe forwardlportion. 55 is directed at an angle to the rear portion so as to move the follower 56 and slide "47.

The slide 30fisalso provided with camslots 57and 58, andi'idirig ,in'each of these slots isa follower 59, one of which is-se'cured to the slide 45 and the other tg the Slide 46. {The slots 57 and 58 stand at an angle to the axis oftihe. gunfor substantially their 'entirelerigths so thatthe reciprocation of the slide. willetfect transverse reciprocation of t hejpawl "slides 45fjand 4 6,"21r1d this 'reciproca'tion will have a greaterrangejthan that given the slide. 47 by the forward portion 55 of thecam slot55. Preferably the ,feed movement of the belt ef fected upon each movemeut of. the, cam plate is proportional to time required for the movement of the bolt in'that direction. That is, if the "recoil occupies 40% of the time of. a complete bolt cycle, the beltuwill be fed adistance equal to 40% of a cartridge pitch during the recoil and the remainder during the runout.

' The operation of the gun may now be briefly described.

. In Fig. 3 of the drawings the parts are shown in the posie members 78 and 79 are adapted to be laterally reciprocated alternately with respect to the axis of the barrel sothat one of the slides movesoutwardly while the other is moving'inwardly -Thus the pawl members 78 and 79 are adapted to alternately engage thebelt links of the belt 71 and effect inward feeding of the belt to centralize wardly, the -.cam plate will be moved therewith, thus I moving'the slides 45 and 46 in an upward direction,

as shown in Figs. 2 and 3, or to the right, as shown in Fig. 4, in order to cause the pawls 49 to engage the link carrying the next cartridge 18. During the firstpart of this movement the follower'56 is engaged in the straight portion 55 of the cam slot 55 so v that the slide47 remains substantially stationary and holds'the' belt im- -mobile while the cartridge 27- is extracted rearwardly from the-belt. During the latter part of the rearward movement of the plate 30, however, the follower 56 rides in theforward portion 55 of the cam slot-and causes the pawl 50 to movethe belt forwardly a given distance by engagement with the cartridge 17 1 When the bolt reaches its rear position, theparts are in the position shown in Figs. 1, 2 and 4. In'this position the cartridge 27 has beenmoved downwardly to be engaged by the extractors Hand is inposition to be rammed forwardly into the chamben Also thebelt has; been moved forwardly a short step fromv the position shown in Fig. 3 so that the link which carried the cartridge'27 is slightly beyond the. axis of the barrel, but the link which carries the car- 'tridgej17 has not yetbeen centered with'the axis of the ;barrel.f r

When thebolt moves forwardly, the cam slots 57 ,and 58 actup'onthe slides 45 and 46 and cause these slides to move to the left, as shown in Fig. 4, and by engaging f the cartridge 18, move thecartridge 17 into a centrally fed position, shown in Fig. 3; It will be seen that. the ammunition belt is fed through the distance of a cartridge pitchin two steps and that the step effected by the pawls 49- upon the forward movement of the cartridge is the greater of the two, this being effected, of course,'by the shape of the camjslots 57 and 58 with respect to the shape ofthe slot 55. It will, of course,'be understood that any desired ratio between the lengths of the two feed steps may be effected by a change in the shape of these cam slots.

. In the formof my'invention shown in Figs. 6 to 10 inclusive, there is illustrated a feed housing '60 connected to thecasing 61 .within which is slidably supported a barrel 62 to which is connected the barrel extension 63. 'In this case the barrel recoils in the usual manner and the barrel extension 63 is connected by alinkag'e 6 4 to a bolt 65" to effect reverse and forward movements of the bolt upon the recoil and return of the barrel, the latter.

being returned "by the spring 66 acting on the barrel extension. I

Depending from the housing 60 are guide rails 67 and 68upon which are supported fins 69.and 70 of the cartridg e 'belt 71, which belt carries cartridges 72 and '73. Thejhousing member 60 is provided upon its lower face with lipped or T-shaped slots 74 and 75 within which are slidablymounted pawl slides 76 and 77. Pivoted to these slide members are pawls 78 and79'urged outwardly from -the slide membersby sp rings 80 and81, as shown more -especially in Fig. 1.0. T A a As will be hereinafter more fully explained the pawl the cartridges or bring them into alignment with the barrel. In the outward movement of the slides the pawls are cammed upwardly against the tension of the springs 80 and 81 so as to ride over the links so as to engage the far sides thereof. r Slidably mounted upon the undersurface of' the boneing 60 is a camplate 82, this plate being supportedin guideway 83 for sliding movement in a longitudinal direction.- At the forward end of the plate is a downwardly extending pin 84 engaged in a socket 85 inthebarrel extension so that movement of the latter effects corresponding movement of the cam plate. v

As shownmore especially in Figs. Sand 9, the cam plate is provided with two cam slots. One of these slots has an intermediate portion86 at an angle to the axis of the barrel and end portions 86 and 86 substantially parallel tothe axis of the barrel. The slide 76 is provided with acam follower87 engaged in this slot. The other slot in the cam plate is also provided with an intermediate portion 88 disposedat an angle to the ,axisof the vbarrel and end portions 88 1a'nd 88 substantially parallel to the' belt,fone of the steps takingplace upon the. rearward movement of the recoil member or barrel'extension and the other taking place upon the forward movement. As shown, these steps are approximately equal but their relative magnitude depends, ofgcqurse, on the configuration of the cam slots'86'and 88 and, if desirecbmore or even all of the feeding movement may be caused to take place upon movement. of the barrel extensionin one direction ortheother. I I p H Pivotally mounted at 90 between arms 91 carried by the housing 60 is a pivoted centralizer 92 having at one end an upwardly directed portion 93. 'The other ortail end of this member 94 is urged downwardly by a spring 95 disposed between the housing 60 and the tail 94 of the lever so as to maintain the lever in the position shown in Fig. 6. Similarly a centralizer 96 is pivoted at 97 to anangle member 98 secured to th'ehousing 60 and is urged, in a counter-clockwise direction about' i'ts pivot by the spring 99. At its forward end the centralizer 96 is provided with a cam lug 100'. 3 Upon the lower side of the came plate82 are provided a pair of lugs '101 and 102, the first of these lugs being adapted to cooperate with'the end 93 of the centralizer 92 andthe second adapted to cooperate with the cam lug 100 of the centralizer'96 to move the centralizers'downwardly to free a cartridge from the belt 71. Itwill be seen from Figs. 6 and 7 that as the cam plate 82 moves rearwardly frornthe position shown in Fig. 6,the lug 101 will strike the end 93 of the centralizer 92 and the'lug 102 will strike'the-lug100 of the centralizer96swinging these members downwardly about their pivots 90 and 97. If the ends of these centralizers are in engagement with a centralized cartridge, shown at 72 in Fig. 6, this causes the cartridge to drop out of the belt 71, as shown at 72 in Fig. 7, into alignment with thebolt 65 '(whichisin its rearward position) so as to be rammed into the chamberupon the forward movement of the bolt. Theoperation' of this modification of my inventionis as follows; As shown in Figs. 6 and 8, the barrel is in its forward position with a cartridge in; the chamber, and

a cartridge pitch from its central position. The slide 76 'is i'n it's outer position as thefollower 87' is at therearend 86 of its cam slot, as shown in Fig.8, and the pawl 78 'is in engagement with the link which holds the cartridge 72. Upon rearward movement of the barrel extension and bolt, the cartridge 72 is first fed into central position by the action of the cam slot portion 86 upon the follower 87, and the-slide 77 -is moved outwardly to engage rearwardly of the next link of the belt 71.

As the slide reaches its rearward position and the follower 87 moves into the slot portion 86 of the cam plate 82, the centralizers 93 and 96 are depressed by the lugs 101, 102 and the cartridge 72, which has just been con tralized, .is positioned downwardly, out of the belt, as

shown at 72 in Fig. 7. The position now occupied by l the parts is shown in Figs. 7, 9 and wherein the barrel ready to be rammed into the chamber and slide 77 has been movedoutwardly with its pawl 79in engagement with the next link of the belt 71, as shown in Fig. 10. When the barrel extension and bolt move forwardly, the slide 77 will be moved inwardly, thus feedingthe next cartridge 73 approximately one-half step into the position formerly. occupied by the cartridge 72 (as shown in Fig. 8). The cartridge at 72 will have been pushed intothe chamber and the parts of the gun are in battery position.

In the form of my invention shown in Figs. 11 to 16 the ammunition belt is fed into' the firearm at a substantially constantspeed. As illustrated, the feed mechanism is applied to a firearm having a spring-urged barrel and barrel extension which, have a substantially constant a celeration in the forward direction from its full recoil position to thefiring position, and a substantially constant deceleration fromthe firing position rearwardly to the recoil position. Also, as illustrated, there is a relatively .shortbelt link at the rear of the cartridge, and, owing sloped forwardly and upwardly. Through this tray is fed a belt comprising links 114 which links carry ca tridges115, 115 and 115 (Fig. 12), the cartridges projecting forwardly from the links. r a (a Slidably mounted withinthe casing 110 is the usual barrel 1 16 and the barrel extension 117, these members being comprised in the barrel assembly and being urged .forwardly by the usualspring 118. A bolt 119 is slidably mounted in the barrel extension and connected thereto by the lever system 120st that the bolt. will be moved forwardly and rearwardly by the recoil and adsauce of, the barrel extension and, of course, through a greater range of movement. The bolt may carry ,an up- Wardly .spring-pressedramming finger 121 to engage a centralized cartridge and move it into the chamber.

A cam plate 122 is slidably mounted at the lower, face of thehousing member 112 which may slide between the positionsshownin Figs. 11. and 13, this cam plate being provided with an opening 123 adaptedto receive-a boss 124mounted on the head 125 of a spring-pressed plunger 126 mounted in a socketinthe barrel'extension 117 and urged upwardly by the spring 127.. Upon the head .1 of the plunger 126 are a 'pair of cam lugs' 123 ladflp t to be received respectively in an opening 129 andia recess 130 in thercarn plate 122. It will be undcrstoodtha this provides an automatically engaging conncctionbfi' tween the barrel extension andthe cam plate 122 such as was explained in the description of the modification of my invention shownin Figs. 1 to 5. That is, the cam lugs 128 will hold the plunger 126 downwardly until theyrcgisterwith the. openings 129 and 13.0 at which time the boss124 will register with; the opening 123. and permit a driving connection to be made. between these parts.

Pivotally mounted at the oppositesides of the housing 112, as shownat. 131 and 132, isa centralizer 133, this centralizer being provided with an actuating lug 134 and a pair of return lugs 135, the latter being formed upon arms 136 extending rearwardly from the body ofthe centralizer. The centralizer supports the cam plate 122 from below against the underside. of the housing 112, and the plate is guided in its forward and return sliding movements by two spherically shaped rollers 137 which operate in slots 138 and 139 formed in the cam plate. These rollers are carriedby pins 140 secured to the housing 112.

The front end of the guide slot 139 is squared, as shown at 141, and makes an actuating face for the front end of the lug 134 on the centralizer 133, and the cam plate also is provided with an elongated opening 142, the rear end ofwhich is substantially square to make an actuating face for one of the return lugs 135 of the centralizer. It will be understood that the other lug 135 is engaged in the opening 142 when the cam plate is inverted in order to be applied to a gun in which the ammunition belt is fed in the opposite direction.

Supported in guide grooves 143 and 144 inthe housing 112 are feed slides 145 and 146, these feed slides carrying spring-pressed pawls 147 and 148 (Fig.' 15) designed to engage the links of the belt 114 and effect the feed thereof. The slide 145 is provided with a follower 149 disposed within a cam slot 150 in the plate 122 having laterally olfset end portions, as shown in Fig. 14, while the slide 146 is provided with a follower 151 disposed in an oppositely contoured slot 152 in the cam plate 122. The-lateral displacements ofthe cam slots are substantially proportional to therunout and recoil time respectively of the recoiling member (in this instance the, barrel assembly) of the firearm so that the feed will, be substantially constant; It will, of course, be obvious withthis arrangement that the slides are alternately actuated in opposite directions by the action of the cam slots 150 and 152 on the followers 149 and 151. The feed slides are tilted forwardly and upwardly at the same angle as the feed tray and belt. 1

Secured to depending lugs 153 carried by the housing 112 is a transversely extending spring member 154 which serves as a bumper for the cam plate 122 at the forward end of its travel. A guide or stop member 156 is carrie by he h us ng 1 2 i h which h f ds-in c rtrid e will substantially come into contact when they reach a centralized position, and pivotally carried adjaeent the outer end of this stop is a spring-pressed linger or flange 157 adapted to engage the cartridges aftcrthfiy have been swung downwardly by the centralizer 135 and hold them in a downwardly. inclined position for feeding into the barrel'chambenwhich position is shown at;115 in Fig. 11

The operation of this form of my invention may now be briefly described. When the barrel extension and cam plate 122 are in recoiled position, as shown in Fig. 11 and Fig. 12 (the earn plate being locked to the barrel ex e s on y h pl n r 126 nd boss 124) and i h the loaded belt seated so that the li carrying cartridge 115 is in the central position aligned for ramming, the

forward movement of the barrel extension begins. a The breech bolt moves forward .at a considerably greater velocity and rams the cartridge 115-clear of the. link 11.

which holds it at an early stage in the runout of the parts. Simultaneously the cam slot 150 forces the slide 145 inwardly so that pawl 1.47 will feed the next link withcartridge 115 inwardly at a substantially constant speed having regard to the contourof the slot and t0 the reasonably constant acceleration of the barrel assembly.

I'Ilns fioves the cartri dge- 113219 the position shown in When the firing station is reached, the explosion halts a ndreverses the-movement of the parts in a ver'y'short time. *The pawl 148'carried by the slide 146 which is operated by the followerlSland slot 152 is moved inwardly during the return or recoil stroke of the cam plate and completes thefeedstrbke at substantially constant lateral velocity. This moves thecartridge from the posi- Uoushown at"115 'in"Fig. 14 to the position shown at 115 in Fig. 12. Toward the end of the rearward movement of the cam' plate the opening 142 passes over the return lug 135 of the centralizer 133, and the actuating lug 134 which has been riding within the slot 139 of the cam plate is depressed by the squared front end of this member. The centralizer, thus depressed, rocks the link of the belt 114 with which it engages and swings the cartridge in that link from the upwardly tilted positron shown at 115 in Fig. 11 to the downwardly tilted position shown at 115 in this figure. During the early part of the following runout after this cartridge 115 has been rammed clear of the link which holds it and the cam plate 122 has moved forward so that the slot 139 again registers over the lug 134 and the lug 135 is contacted by the squared rear end of the opening 142, the centralizer is returned to its upward or inactive position.

While I have shown and described some preferred embodiments of my invention, it will be understood that it is not to be limited to all of the details shown, but is capable of modification and variation within the spirit of the invention and within the scope of the claims.

What I claim is:

1. In an ammunition feed belt system for an automatic firearm having a housing and a longitudinally reciprocable element therein actuated by discharge of the firearm, a member operatively mounted in the housing for tran'slatory reciprocating movement in a direction transversely of the housing, said member having pawl means to engage and feed the ammunition belt, and connecting means between said element and said member to effect transverse reciprocation of the latter upon longitudinal reciprocation of the former, said connecting means comprising an actuator connected to said element to reciprocate therewith longitudinally of the housing and provided with a cam slot and a follower carried by said member and engaged in said slot.

2. An ammunition feed belt system as in claim 1 wherein a second transversely reciprocating member is provided in the housing to feed the ammunition belt and carries a follower engaged with a second cam slot in said actuator and wherein said second member is moved in a feeding direction alternately with said first member.

3. An ammunition feel belt system as in claim 1 wherein a second transversely reciprocating member is provided in the housing to feed the ammunition belt and carries a follower engaged with a second cam slot in said actuator and wherein said second member is moved in a feeding direction alternately with said first member, and one of said members acts during recoil of said longitudinally reciprocable element and the other during runout thereof. I

4. An apparatus as in claim 2 wherein the cam slots are so shaped that said members are moved at substantially constant speed.

5. In an ammunition feed belt system for an automatic firearm having a housing and a longitudinally reciprocable recoiling member therein actuated by discharge of the firearm, an ammunition feed tray supported by the housing and sloped at a substantial angle to the barrel axis, a substantially longitudinally sliding cam plate connected to the recoiling member to be reciprocated therewith in a longitudinal direction, a springurged feed pawl mechanism actuated by the cam plate in a translatory movement and in a direction substantially smart transverse to the direction ofrnovement of the latter, said pawl mechanism comprising a slide member between the cam plate'and the housing and said housing having a' guide' groove in which said slide member isrnounted.

6. A mechanism as in claim 5 wherein the connection between thepawl mechanism and the cam plate comprises a cam groove in said plate, a portion of which is at an'angle'to the barrel axis, and a follower on said pawl mechanism engaged-in said groove.

7. A mechanism as in claim 5 'whe rein'said guid grooves in the housing are tilted at substantially the same angle as the tray.

8. In an automatic firearm, a receiver, a cover housing 'movably mounted thereon, a reciprocable recoiling member therein actuated by discharge of the gun, an ammunition belt feed system including a longitudinally sliding member in the housing connected to the recoiling member to be actuated thereby, a transversely movable member having a feed pawl thereon adapted to engage and feed the ammunition belt, said last-named member being actuated by said longitudinally sliding member, a cartridge-depressing member movably carried by the housing to engage and move a centralized cartridge to ramming position, and means on said longitudinally sliding member to engage and actuate said cartridge-depressing member.

9. A mechanism as in claim 8 wherein means are provided to efiect a positive return of said cartridge-depressing member to normal position after it has been moved by said longitudinally sliding member.

10. A mechanism as in claim 8 wherein a pair of car tridge-depressing members are provided to strip the cartridge from the belt in a downward direction.

11. An ammunition belt feed system as in claim 8 wherein a spring detent member is pivotally mounted in the housing about an axis substantially parallel with the barrel axis to engage over a cartridge after depression thereof and retain the cartridge in depressed position.

12. In an ammunition feed belt system for an automatic firearm having a housing and a longitudinally re ciprocable recoil member actuated by the discharge of the firearm, a longitudinally sliding cam plate connected to the recoiling member to be actuated thereby, a feed member operatively mounted in the housing for trans latory reciprocating movement in a direction transverse to that of the movement 'of the cam plate and having pawl means to engage and feed the ammunition belt, said cam plate being provided with a cam slot and said transversely reciprocating member having a follower engaged in said slot, said connection between the recoiling member and said cam plate comprising a spring-pressed plunger upon one of said members and an opening in the other member to engage said plunger.

13. In an ammunition feed belt system for an automatic firearm having a housing and a longitudinally reciprocable recoil member actuated by the discharge of the firearm, a longitudinally sliding cam plate connected to the recoiling member to be actuated thereby, a feed member operatively mounted in the housing for translatory reciprocating movement in a direction transverse to 'that'of the movement of the cam plate and having pawl means to engage and feed the ammunition belt, said cam plate being provided with a cam slot and said transversely reciprocating member having a follower engaged in said slot, said connection between the recoiling member and said cam plate comprising a spring-pressed plunger upon one of said members and an opening in the 11 the cam plate and a sphericai roller carried by the pawl meehanismand engaged in saidgraove.

' 1s. Mechanism fast in claim 3 wherein the cam s lbts I are so shepedstthatl the distance over which the belt is mqyed by'one pawl! is unequal to; that over which it is mmted by the other pawl. t i t t I I 16. Mechanismas in claim 3 whereinthe cam slots areso, shaped that the distance over which the belt is moved by one pawl is unequal to that over which it is I moved by the other pawl and is: pgoportional' to the time 10 occupied by each part of the feed cycle.

'12 References Citedin the fileof this patent UNITED STATES PATENTS I 'e-n; ugie L3, :1907

France Mar. 23, 1945 t 

